Nowadays, with the development of electronic devices, apparatuses for the convenience of the driver are being developed to improve functions associated with the performance and safety of a vehicle. In particular, there is growing interest in a head-up display (HUD) of the vehicle.
The HUD is designed to display driving information on the windshield of a vehicle or airplane. Initially, the HUD has been introduced to ensure that a pilot is able to view information in the front view. However, the HUD has been recently introduced in vehicles to reduce accidents.
The HUD of a vehicle displays a variety of vehicle information, such as arrow information for guiding path changes operating in conjunction with a navigation device, and text information indicating the speed of a vehicle, on the windshield glass or in the form of augmented reality beyond the windshield glass, thereby preventing a driver's gaze from being dispersed. In other words, for the purpose of verifying vehicle information, a driver may not need to move his/her eyes in the direction of the terminal providing the corresponding information. The HUD helps improve the driver's safety because the driver can drive while looking at the front view in which the head-up display image is displayed.
Furthermore, there is a need for a separate display means capable of displaying an increasing amount of vehicle information as more devices for the convenience of the driver are mounted in a vehicle. Accordingly, there is a growing interest in the HUD as there is a need for the space for separately accommodating these display means.
The general HUD may include an image generator, a mirror device, and a controller. After being reflected from the mirror device, a video image displayed by the image generator (e.g., a video image corresponding to various pieces of vehicle information received from an Electronic Control Unit (ECU) in a vehicle) is projected onto the windshield of the driver's seat.
As such, while driving, the driver of a vehicle not only may keep his/her eyes forward but also may verify various pieces of information necessary to drive the vehicle, such as the driving information or the navigation information of the vehicle, through the virtual image projected within the range not departing from the field of vision at the same time.
However, since the general head-up display fixedly projects a virtual image at a specific preset location, the physical condition of the driver or the movement of the driver are not considered. Accordingly, the image projected by the head-up display system is not exactly matched with the road.